首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   61542篇
  免费   5406篇
  国内免费   2561篇
耳鼻咽喉   688篇
儿科学   1540篇
妇产科学   1138篇
基础医学   6244篇
口腔科学   1158篇
临床医学   5844篇
内科学   5662篇
皮肤病学   775篇
神经病学   2182篇
特种医学   3383篇
外国民族医学   52篇
外科学   7669篇
综合类   10477篇
现状与发展   19篇
预防医学   1688篇
眼科学   608篇
药学   4321篇
  46篇
中国医学   1878篇
肿瘤学   14137篇
  2024年   167篇
  2023年   945篇
  2022年   2042篇
  2021年   2682篇
  2020年   2143篇
  2019年   1910篇
  2018年   1780篇
  2017年   2029篇
  2016年   2286篇
  2015年   2467篇
  2014年   3722篇
  2013年   3781篇
  2012年   3413篇
  2011年   3779篇
  2010年   3067篇
  2009年   3095篇
  2008年   3100篇
  2007年   3359篇
  2006年   3017篇
  2005年   2684篇
  2004年   2318篇
  2003年   1956篇
  2002年   1823篇
  2001年   1631篇
  2000年   1332篇
  1999年   1214篇
  1998年   1047篇
  1997年   969篇
  1996年   843篇
  1995年   756篇
  1994年   634篇
  1993年   501篇
  1992年   410篇
  1991年   341篇
  1990年   268篇
  1989年   257篇
  1988年   252篇
  1987年   212篇
  1986年   159篇
  1985年   204篇
  1984年   185篇
  1983年   112篇
  1982年   148篇
  1981年   124篇
  1980年   85篇
  1979年   84篇
  1978年   60篇
  1977年   42篇
  1976年   37篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
本院1966年~1989年共收治小儿卵黄囊瘤37例,经血清甲胎蛋白(AFP)测定,光镜确定诊断又通过10例电镜观察,8例AFP免疫组化观察,文献复习,本文支持Teilum提出该瘤来源于卵黄囊瘤背壁的全能性生殖细胞的组织发生观点;1.胚胎卵黄囊有合成AFP能力,本文意儿血清AFP明显升高,免疫酶标可作AFP定位。2.超微结构观察:肿瘤形态与妊娠7周卵黄囊相似,电镜下可见到上皮性及间叶性成份相当于胚外内胚层及胚外中胚层成份。且讨论了该瘤的命名与畸胎瘤关系和免疫组化的应用  相似文献   
72.
As part of the strategy for the design of macromolecular carriers for drug targeting, the disposition characteristics of macromolecules were studied in mice bearing tumors that served as target tissues. Eight kinds of macromolecules including four polysaccharides and four proteins with different molecular weights and electric charges were used; tissue distribution and tumor localization after intravenous injection were studied. Pharmacokinetic analysis revealed that the tissue radioactivity uptake rate index calculated in terms of clearance was different among the tested compounds; especially, the urinary radioactivity excretion clearances and the total hepatic radioactivity uptake clearances varied widely. Compounds with low molecular weights (approximately 10 kD) or positive charges showed lower tumor radioactivity accumulation; radioactivity was rapidly eliminated from the plasma via rapid urinary excretion or extensive hepatic uptake, respectively. On the other hand, large and negatively charged compounds, carboxymethyl dextran, bovine serum albumin, and mouse immunoglobulin G, showed higher radioactivity accumulation in the tumor (calculated total amounts were 15.6, 10.8, and 20.8% of the dose, respectively) and prolonged retention in the circulation. These results demonstrated that the total systemic exposure rather than the uptake rate index was correlated with total tumor uptake. Molecular weight and electric charge of the macromolecules significantly affected their disposition characteristics and, consequently, determined radioactivity accumulation in the tumor. It was concluded that a drug–carrier complex designed for systemic tumor targeting should be polyanionic in nature and larger than 70,000 in molecular weight.  相似文献   
73.
HepatocelularCarcinomawithTumorThrombusinPortalVein:FindinginUltrasonography,ComputedTomography,AngiographyandChemoembolizati...  相似文献   
74.
Dermatofibrosarcoma protuberans (DFSP) previously called Morbus Darier is an intermediate grade sarcoma with a fairly high rate of recurrence, it occurs most commonly on the trunk and extremities but may also occur in the head and neck region. Treatment of choice is wide excision. A 69-year-old female patient with a 57-year history of dermatofibrosarcoma protuberans is presented. The lesion appeared on the right forehead and both eyelids at the age of 12 years. The patient required 64 surgeries mostly for the head and neck lesions.  相似文献   
75.
There is a growing body of evidence that the cytokine, tumor necrosis factor-α (TNF-ga), plays an important role in the development of hepatic ischemia/reperfusion injury. We found that the immunosuppressants, cyclosporine-A (CsA), azathioprine, and FK506, have protective effects on such injury. The purpose of the present study was to elucidate mechanisms involved in these beneficial effects of the immunosuppressant, CsA, on liver injury following cold preservation and transplantation, with special reference to the suppression of TNF-α release. Rat livers were stored in Euro-Collins solution (EC) at 4°C for 6h and orthotopically transplanted. The animals allotted to two groups: group A (untreated controls) and group B (CsA pretreatment of recipients). CsA (10 mg/kg, p.o.) was given for 3 consecutive days preoperatively. CsA pretreatment of the recipients significantly improved the 2-week survival rate (0/6 for group A, 3/6 for group B;P<0.05) and this was associated with a significant decrease in serum TNF-α levels 2h posttransplantation (group A, 69.8±15.7 pg/ml; group B, 22.8±6.8; mean±SEM;n=12 each;P<0.05) and amelioration of sinusoidal endothelial injury, assessed by electron microscopy. Plasma endotoxin levels following reperfusion of the grafts were not altered by the CsA therapy. Morphologically, CsA pretreatment of the recipients did not alter activation of Kupffer cells. CsA pretreatment of the recipient aids in preventing cold preservation/reperfusion injury of the liver graft, possibly by modulating effects of TNF-α.  相似文献   
76.
骨与关节肿瘤和瘤样病变1084例统计分析   总被引:5,自引:0,他引:5  
目的:分析青海高原地区骨与关节肿瘤及瘤样病变的发病情况。方法:对1963~1995年10月的1084例骨与关节肿瘤及瘤样病变进行了统计分析。结果:良性骨肿瘤722例(66.61%),恶性骨与关节肿瘤249例(22.97%),瘤样病变113例(10.42%),良、恶性肿瘤之比为2.9∶1,男女之比为1.22∶1,好发年龄为11~30岁,好发部位为胫骨(27.3%),其次为股骨(21.8%)。良性骨肿瘤以骨软骨瘤(54.43%)、软骨瘤(21.19%)、骨巨细胞瘤(9.97%)多见。原发恶性骨肿瘤以骨肉瘤(33.3%)、软骨肉瘤(10.85%)、骨髓瘤(10.05%)多见。瘤样病变则以孤立性骨囊肿(46.01%)和骨纤维结构不良(30.97%)多见。结论:本组结果与国内文献对比有许多相似之处,但良性骨肿瘤与恶性骨肿瘤之比与国内文献有较大不同,可能与高原环境有关。  相似文献   
77.
A case is reported of Wilms' tumor associated with multiple pulmonary metastases histologically showing maturation of the tumor cells at 9 years after the resection of the primary tumor and intensive therapy. A huge tumor of a 22-month-old patient's right kidney was resected. The tumor was diagnosed as Wilms' tumor of mesenchymal type (stage 1), which consisted of predominantly immature mesenchymal tissue including rhabdomyoblasts, smooth muscle and fibrous tissue, and few blastemal and epithelial components. Intensive preoperative and postoperative chemotherapy with actinomycin D and vincristine and postoperative irradiation therapy totaling 16 Gy were carried out. The patient was regularly followed up uneventfully until 9 years after the surgery. On routine chest x ray at the age of 10 years 11 months, multiple pulmonary nodules were found. The excised nodules from the bilateral lungs disclosed similar histology, exclusively composed of dense collagen bundles and fibrocytes intermingled with mature striated muscle bundles. No immature tumor components were detected. The possible effect of intensive therapy in this maturation was stressed, although spontaneous benign differentiation of tumor cells cannot be excluded.  相似文献   
78.
报道显微手术治疗10例延颈髓交界处髓内肿瘤(ITCJ),肿瘤全切除6例,次全切除4例,无手术死亡,70%病例术后好转。ITCJ可分为颈延型和延颈型两大类型。MRI是诊断本病的主要方法,并且具有指导手术的重要意义。结果也表明,显微手术方法和术后呼吸功能监护很有必要。  相似文献   
79.
目的:分析立体定向X-刀放射治疗颅内肿瘤后的近期疗效,并进行阶段性工作总结。材料和方法:53例不同类型脑瘤患者,以CT、MR、DSA图像资料作为定位依据,用德国Brain LAB治疗计划系统设计三维优化方案,西门子MD-2型直线加速器旋转照射。结果:53例患者经X-刀治疗后,近期均取得了满意效果,诸如以卡氏评分法评价,临床症状有所改善;以CT增强扫描复查观察,肿瘤大小趋于缩小或消失。结论:立体定向放射治疗后的追踪观察表明,只要严格掌握适应症,精确定位,精确计划,精心治疗,X-刀是一种安全、有效、无痛苦的治疗脑肿瘤的方法。它可起到改善临床症状,提高患者生活质量,延长生存期限的作用。  相似文献   
80.
瘤体骨切除灭活再植治疗四肢长骨巨细胞瘤   总被引:21,自引:0,他引:21  
体内刮除及灭活植骨治疗骨巨细胞瘤(GCT)的复发率高。我科从1986年6月~1996年2月治疗四肢长骨GCT24例。随访11个月~8年4个月。其中7例采用局部切刮体内灭活植骨和(或)骨水泥充填治疗。结果1例感染,6例复发,1例恶变后死于肺转移。作者自1991年1月采用瘤体骨切除,离体灭活再植,与骨残端体内灭活相结合,骨缺损采用自家腓、髂骨移植,L-梯形加压钢板(L-TCP)或梯形加压钢板(TCP)固定治疗17例,其中12例保留关节,5例做膝关节融合。本组无菌创口感染1例,1例复发。在保留关节的12例中9例关节功能恢复优良,1例尚可,2例差。充分说明瘤段骨切除体外灭活再植术疗效确实,复发率低。保留关节术式适于关节破坏较轻(<=1/2)者,结合关节残端体内灭活和有效的骨结构重建,有利于恢复关节功能。如关节面累及>1/2,宜做骨关节端切除,灭活再植,下肢宜做关节融合或人工关节置换术。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号